1. Field of the Invention
The present invention relates to an automatic clutch control device and a gear change control method therefor which perform an automatic engaging control of a clutch at the time of the starting and stop of a vehicle and a gear change.
2. Discussion of the Related Art
In automatic clutch control devices in the prior art, in order to suppress a gear change shock at the time of the engagement of a clutch, it may be the case that the rotational speed of an engine is changed at a predetermined change speed to be synchronized with the rotational speed of an input shaft of a transmission. In this case, the clutch torque of the clutch is set to become a predetermined target value, so that it is possible to control the change speed in the rotational speed of the engine. Because of being fluctuated in dependence on an engaging degree of the clutch (the engaging amount of the clutch), the clutch torque of the clutch can be adjusted by controlling the operation amount of an actuator which operates the clutch.
For example, in JP10-318288 A, there is set a reference value for the engaging amount of the clutch that is used in obtaining a target clutch torque based on an accelerator opening degree and a vehicle speed. The target clutch torque is calculated first by calculating a target inertia torque by multiplying the inertia of the engine with a target rotational speed changing speed of the engine in a gear change and then by subtracting the target inertia torque from a current output torque of the engine. Thus, it results that the magnitude of the target clutch torque calculated in this way is set as the magnitude depending on the operating degree (pressing-down amount) of an accelerator which determines the current output torque of the engine.
As described above, in the engaging control of a clutch in the prior art, even when the driver presses down on the accelerator at a high speed for a large acceleration, the magnitude of the target clutch torque is determined in dependence upon the pressing-down amount of the accelerator without taking such pressing-down speed into consideration. Therefore, there occurs a situation that an acceleration wanted by the driver cannot be attained and hence, that the demand of the driver cannot be satisfied.